1. The Field of the Invention
The present invention is in the field of light curing devices and, more particularly, to the field of lenses configured for use with dental light-curing devices.
2. The Relevant Technology
In the dental industry, dental cavities are often filled and sealed with photosensitive compounds that are cured by exposure to radiant energy, such as visible light. These compounds, commonly referred to as light-curable compounds, are placed within dental cavity preparations and onto dental surfaces where they are subsequently irradiated by light.
The radiated light causes photosensitive components within the compounds to polymerize, thereby hardening the light-curable compounds within the dental cavity preparation or another desired location.
The light is typically directed to the light-curable compounds with a light-curing device that includes a lamp, such as a halogen lamp bulb, or a Light-Emitting Diode (LED) that is configured to generate light within a spectrum suitable for curing the light-curable dental compounds. Light curing devices also typically include a light guide, such as a fiber optic wand, or a specialized tip or lens that can capture, collimate or otherwise redirect the light within the patient's mouth, where the light is finally dispersed.
One problem with existing light curing devices, however, is that the light-guides are often unable to properly direct the dispersed light to the desired location within the patient's mouth and in the desired manner. For instance, some light guides are unable to properly direct the light within a contained area where the light-curable compounds are located. This is a particularly true of many LED light-curing devices because of the wide angle of dispersion in which LEDs emit light. This is a problem because the improperly dispersed light may irritate sensitive mouth tissues and prevent the light-curable compounds from curing properly.
During certain dental procedures, such as treatment of deep Class II fillings, it is necessary for the light to be directed deep into the dental preparation and with sufficient intensity to cure the light-curable compounds placed therein. To facilitate the dispersion of light within a Class II preparation, or any other deep preparation, it is sometimes desirable to use a cone-shaped tip or lens that can be inserted within the dental preparation, thereby enabling the radiated light to be dispersed within the desired treatment area.
FIG. 1 illustrates one example of an existing conical lens 10 that may be utilized with a light-curing device to help disperse light within a dental preparation. One problem experienced with this existing lens 10, however, is that it can cause the light to be dispersed from the lens 10 in such a manner that a pocket or void 12 of light occurs directly in front of the lens 10, as shown. This void 12 is undesirable because it can effectively prevent curing of any light-curable compound disposed directly in front of the lens 10 during the irradiation procedure, thereby preventing uniform curing of the light-curable compounds within the dental preparation.
The void 12 of light that occurs directly in front of the lens 10 is an observable result of Snell's law in which light is refracted by the materials through which the light travels. Snell's law is well-known to those of ordinary skill in the art. The angle at which the light is refracted by the lens is a function of both the material properties (e.g., index of refraction) of the lens 10 and the angle at which the light intersects the outer surface of the lens 10 (e.g., angle of incidence).
In view of the foregoing, there is currently a need in the art for improved tips that can be used with light-curing devices for curing light-curable compounds during dental procedures, particularly for use in Class II dental procedures.